In a so-called three-door car or five-door car, a luggage space defined directly behind the rear seats is directly connected with the passenger compartment as opposed to a trunk space of a normal passenger car which is substantially enclosed by the car body, and a tail gate or a door for the rear end of the car is provided for the access to this luggage space from the rear end of the car in substantially the same way a trunk lid is provided for a trunk provided in the rear end of a normal passenger car. The tail gate may be hinged either at its upper end to the rear end of the roof or at its lower end to the rear end of the floor. Alternatively, the tail gate may be hinged at its side end to the side wall of the car body. In such a vehicle having a tail gate, a rear shelf is often provided in the rear of the rear seats so as to hide the luggage space from the view of the passengers. Typically, a rear shelf is hinged at its forward end to a fixed member which is fixed adjacent to the rear surface of an upper part of the rear seats.
Since the rear shelf is often required to be lifted up to allow easy access to the luggage space particularly when bulky luggage is to be stored in the luggage space, it is convenient to have the rear shelf lift itself automatically when the tail gate is opened. According to a known structure, a cable is connected to the rear shelf at its one end and to a part of the tail gate at its other end so that the tension applied to the cable upon opening of the tail gate may lift the rear shelf out of the way. However, since the length of the cable is fixed, a slight misadjustment of the length of the cable or excessive slack in the cable when the tail gate is fully open. In the former case the cable could be broken by the inertia of the tail gate when it is forcibly opened and in the latter case the rear shelf will not lift itself to a sufficient extent and the rear shelf will droop down when the tail gate is fully open. Furthermore, the slack in the cable when the tail gate is closed is not only unfavorable from an aesthetic view point but also could be caught by luggage or a part of the car body.
Under this circumstance, it is conceivable to provide a cable retractor having a spring loaded reel for winding the cable thereinto so that no excessive tension nor excessive slack may develop in the cable. However, when the cable is to be fully taken out from the reel when the door is fully open, the cable may still be subject to an excessive tension. If part of the cable is to be left wound on the reel even when the tail gate is fully open, then the tension in the cable may not be sufficient to keep the rear shelf in its uplifted state since the lift of the rear shelff is determined by the balance between the weight of the rear shelf itself and the spring force of the reel. If the spring force of the retractor is increased so as to oppose the tendency of the rear shelf to droop, then the force required to open the tail gate will unduly increase.